1035Vol. 10 | No. 4 | Autumn 2013 |U R O LO G Y J O U R N A L Department of Urology, First Hospital of Jilin Uni- versity, Changchun, China Yanbo Wang, Zhihua Lu, Jinghai Hu, Xiaoqing Wang, Ji Lu, Yuanyuan Hao, Yan Wang, Qihui Chen, Fengming Jiang, Haifeng Zhang, Ning Xu, Yuchuan Hou, Chunxi Wang Renal Access by Sonographer versus Urologist during Percutaneous Nephrolithotomy Corresponding Author: Chunxi Wang, MD Department of Urol- ogy, The First Hospital of Jilin University, 71 Xinmin Street, Changchun, Jilin Province, China. Tel: +86 0431 8878 2321 Fax: +86 0431 8187 5801 Email: chunxi_wang@126. com Received August 2012 Accepted February 2012 Purpose: To evaluate the percutaneous access outcomes and complications following percutane- ous nephrolithotomy (PCNL) that was obtained by sonographer or urologist at a single academic institution. Material and Methods: A retrospective chart review of 259 patients who underwent PCNL was performed. Patients were stratified according to percutaneous access by sonographer (group 1) or urologist (group 2) in 174 and 85 patients, respectively. Demographic, stone characteristics, op- erative variables, percutaneous access complications and stone-free rates were compared between groups. Results: The major complication rate and minor complication rate, mean blood loss and rates of blood transfusion were comparable between groups. Compared with urologist, sonographer pre- ferred to choose subcostal rib puncture instead of intercostal rib puncture. The lower calyx was the most frequent site of target calyx puncture in group 1 (165 cases, 94.8%), while the percentage of lower calyx in group 2 was 82.3% (72 cases) (P = .001). The overall stone-free rates were sig- nificantly higher in group 2 than that in group 1 (90.6% vs. 79.9%, P = .03). In group 1, 23 cases (13.2%) needed post-operative extracorporeal shock wave lithotripsy (SWL), while, the percentage of post-operative SWL in group 2 was only 4.7% (4 cases) (P = .035). Conclusions: Renal access in PCNL can be safely and successfully obtained by both sonographer and urologist. Infracostal and lower calyx access in our study has poor stone-free rates and so- nographer prefers infracostal and lower access. We encourage urologists establish renal access by themselves during PCNL. Keywords: nephrostomy; percutaneous; retrospective studies; ultrasonography; treatment out- come; physician's role. ENDOUROLOGY AND STONE DISEASE 1036 | INTRODUCTION Percutaneous nephrolithotomy (PCNL) has become a mainstay for the treatment of renal stones since the first successful removal of a renal calculus via a nephrostomy tract in 1976(1) Implications of PCNL include stones > 2.0 cm in diameter, complex and special renal stones. In China, historically, access to the kidney for stone has been performed by radiologists or sonographers. Recent studies compare the outcomes of renal access for PCNL that is obtained by radiologists or urologists.(2-5) However, to our knowledge, no study has yet been discussed about the dif- ference between sonographers and urologists. We evaluated percutaneous access for PCNL that was obtained by sonog- rapher or urologist and compared access outcomes and com- plications. MATERIAL AND METHODS Clinical data A total of 259 patients (148 men and 111 women, mean age 42.1 years, range from 20 to 67 years) were prospectively enrolled in this study from January 2009 to May 2012 in the First Hospital of Jilin University. Patients were stratified ac- cording to percutaneous access by sonographer (group 1) or urologist (group 2) in 174 and 85 patients, respectively. Patients in group 1 were consecutively performed by sonog- rapher from January 2009 to May 2011. Patients in group 2 were consecutively performed by urologist from May 2011 to May 2012. Preoperative factors that were analyzed includ- ed gender, age, body mass index (BMI), stone position, mean maximum stone diameter, presence of hydronephrosis, stone type (complete staghorn, partial staghorn or pelvic), associ- ated comorbidities (hypertension, diabetes mellitus, pulmo- nary disease or coronary artery disease) and previous medi- cal or surgical history. Kidney patients were excluded from the study if they had 1 phase nephrostomy. All surgeries were finished by the same surgeon. Furthermore, the sonographer was the same person in this study. Procedure of PCNL The entire procedure was performed under general anesthe- sia. Ureteral catheter was inserted retrograde into the pelvi- caliceal system with the patient in lithotomic position. The patient was repositioned to the prone position and a specially designed cushion was placed on the table to enable a deflect- ed position. An 18-gauge coaxial needle (Cook Inc., Bloomington, Indi- ana, USA) was introduced into the targeted calyx under the guide of Doppler ultrasound (Aloka 5) by the sonographer or surgeon. Selection of the targeted calyx and number of access tracts were dependent on stone location, pelvicaliceal anatomy and the preference of sonographer or surgeon. The working channel was then dilated by using the plastic dilator system (Cook Inc., Bloomington, Indiana, USA) or X-Force Nephrostomy Balloon Dilation Catheter (BCR Inc., Tainan, Taiwan), followed by placement of either 18F or 26F work- ing sheath. The Lumenis 60 w lithotripter (Lumenis, Santa Clara, CA, USA) or Cybersonics Double-catheter system (Gyrus/ACMI, Southborough, Mass., USA) was used to fragment the renal stone. At the end of the procedure, an X-ray check for re- sidual stone fragments was performed. A 20 Fr Foley catheter was placed as a nephrostomy tube and it was removed if there was no extravasation at approximately 3 days post-operation. Patients were considered stone-free when no stone > 4 mm was visualized. Residual fragments > 5 mm in diameter were treated with extracorporeal shock wave lithotripsy (SWL) or the second phase PCNL. Major complications were considered as septicemia, hemor- rhage requiring angiographic renal embolization or nephrec- tomy, thoracic or abdominal organ injury, acute pancreatitis. Transient fever, clinically insignificant bleeding, urinary tract infection without signs of urosepsis, renal colic, and pro- longed urinary leakage from the percutaneous access were considered minor complications. Statistical analysis The statistical package for the social science (SPSS Inc, Chi- cago, Illinois, USA) version 15.0 was used for all statistical analyses. Comparisons were made using Student’s t tests and Pearson’s chi-square tests, where P value < .05 was consid- ered statistically significant. RESULTS Of the 259 patients reviewed, 67.2% and 32.8% underwent percutaneous access by sonographer or urologist, respective- ly. The patients and stone characteristics of the study groups are summarized in Table 1. There was no statistically signifi- cant difference between the groups with regard to sex, age, Endourology and Stone Disease 1037Vol. 10 | No. 4 | Autumn 2013 |U R O LO G Y J O U R N A L mean BMI, stone position, stone diameter, presence of hy- dronephrosis, stone type (complete staghorn, partial staghorn or pelvic), associated comorbidities (hypertension, diabetes mellitus, pulmonary disease or coronary artery disease) and previous medical or surgical history. Double accesses were required in 8 cases (4.6%) in group 1 and in 6 cases (7.1%) in group 2 (P < .05) (Table 2). Sonog- rapher preferred to choose subcostal rib puncture (166 cases, 95.4%) instead of intercostal rib puncture (8 cases, 4.6%), however, in urologist group, 74 cases (84.7%) were subcos- tal rib puncture and 13 cases (15.3%) were intercostal rib puncture (P = .003). The lower calyx was the most frequent site of target calyx puncture in group 1 (165 cases, 94.8%), while the percentage of lower calyx in group 2 was 82.3% (72 cases) (P = .001). The major complication rate (1.7% vs. 1.2%; P = .737) and minor complication rate (7.5% vs. 8.2%; P = .829) were com- parable between groups. Mean blood loss and rates of blood transfusion were also similar between groups. The overall stone-free rates were significantly greater in the urology ac- cess group than that in the sonographer access group (90.6% vs. 79.9%, P = .03). There was no statistically significant difference between the groups with regard to mean opera- tion time (defined as the time from ureteral catheterization to the placement of the nephrostomy tube), mean hospital stay and stage 2 PCNL. However, 23 cases (13.2%) needed post- operative SWL in group 1 and the percentage was only 4.7% (4 cases) in group 2 (P = .035). DISCUSSION Improvement of technology and increasing experience has led to enhancement of safety and efficacy of PCNL. Howev- er, reported complication rates still reach 3% to 18% accord- ing to different scholars.(6-8) Proper selection of the targeted calyx and successful puncture could raise the stone-free rate and avoid injuring important blood vessels. Dependent on the ultrasonography or fluoroscopy guided PCNL, histori- cally, access to the kidney for stone treatment has been per- formed by sonographers or radiologists. However, recently, in the past several years, urologists attempted to puncture by themselves.(9,10) Recent studies discussed the outcomes of percutaneous access for PCNL that was obtained by ra- Renal Access by Sonographer in PCNL | Wang et al Table 1. Patients and stones characteristics in the two study groups. Sonographer-made access (Group 1) Urologist-made access (Group 2) P Patients, no. 174 85 ----- Male to female ratio 96/78 52/33 .359 Mean age, year (range) 41.6 (21-65) 42.5 (20-67) .745 Mean BMI, kg/m2 25.3 (20-28) 24.6 (21-28) .426 Renal/Ureter stone, no. 139/35 63/22 .293 Stone side, right/left 88/86 45/40 Mean maximum stone diameter, cm (range) 3.2 (1.6-7.2) 3.1 (1.8-6.8) .395 Hydronephrosis, yes/no 151/23 69/16 .236 Stone type, n (%) Complete staghorn 31 (17.8) 16 (18.8) .843 Partial staghorn 45 (25.9) 23 (20.1) .837 Pelvic 62 (35.6) 34 (40) .494 Multiple stones, no. 102 (58.6) 58 (68.2) .135 Associated comorbidities n (%) Hypertension 23 (13.2) 10 (11.8) .742 Diabetes mellitus 12 (6.9) 7 (8.2) .698 Pulmonary disease 9 (5.2) 5 (5.9) .812 Coronary artery disease 8 (4.6) 5 (5.9) .657 Previous medical and surgical history (%) 8 (4.6) 5 (5.9) .657 1038 | diologists or urologists. To our knowledge, no study has yet been discussed about the difference between sonographers and urologists. Jeffrey and colleagues(11) retrospectively evaluated PCNL performed by interventional radiologists or urologists with regard to use of multiple access tracts, percentage of su- pracostal tracts, mean access difficulty parameters, access- related complications, overall stone-free rate and additional access tract placement at the time of surgery. Access-related complications were the same in the two groups. However, overall stone-free rate was higher in the urologists’ access group, and 36.8% of access obtained by radiologists could not be used, which need additional access at the time of sur- gery. Conversely, El-Assmy and colleagues(2) found that ac- cess related complications and stone-free rates were compa- rable in urologist group and radiologist group. In this study, there was no statistically significant difference between the groups with regard to major and minor compli- cations. Three cases (1.7%) in group 1 and 1 case (1.2%) in group 2 encountered septic shock which was considered ma- jor complications. Minor complications were comparable in both groups (7.5% vs. 8.2%, P = .829). Mean blood loss and rates of blood transfusion were also similar between groups. The reasons of high stone-free rates in the urologist-made ac- cess group, in our opinion, were that sonographer was not fa- miliar with and not care about the subsequent steps of PCNL. Furthermore, compared to urologist, sonographer preferred to subcostal rib puncture (95.4%) and lower calyx puncture (94.8%). Lack of suitable intercostal rib puncture and middle calyx puncture might result in the difficult fragment during PCNL. The lower stone-free rate in sonographer-made ac- cess group resulted in higher stage 2 SWL. Our study has several limitations. Main limitation of study was that it was not randomized and prospective. A selection bias is inherent for its retrospective nature. Furthermore, the number of cases in the study was comparatively smaller, which result in lack of enough confidence on statistical anal- ysis of the data. CONCLUSION Renal access in PCNL can be safely and successfully ob- tained by both sonographer and urologist. Infracostal and Endourology and Stone Disease Table 2. Operative details and outcomes in the two study groups. Sonographer-made access (Group 1) Urologist-made access (Group 2) P No. of sites required (%) Single 166 (95.4) 79 (92.9) .411 Multiple 8 (4.6) 6 (7.1) No. of rib puncture (%) Subcostal 166 (95.4) 72 (84.7) .003 Intercostal 8 (4.6) 13 (15.3) Calyx puncture (%) Lower 165 (94.8) 70 (82.3) .001 Middle 9 (5.2) 15 (17.7) Upper 0 0 Mean operative time, min (range) 74.5 (43-145) 75.6 (38-163) .853 Stone free rate, n (%) 139 (79.9) 77 (90.6) .03 Mean hospital stay, day, (range) 8.2 (6-16) 7.9 (6-15) .385 Stage 2 PCNL, n (%) 8 (4.6) 1 (1.2) .158 Stage 2 ESWL, n (%) 23 (13.2) 4 (4.7) .035 Mean blood loss(ΔHb), g/dL -2.2 (3.5-0.4) -2.3 (3.6-0.4) .355 Need of blood transfusion, n (%) 4 (2.3) 3 (3.5) .566 Major complications, n (%) 3 (1.7) 1 (1.2) .737 Minor complications, n (%) 13 (7.5) 7 (8.2) .829 1039Vol. 10 | No. 4 | Autumn 2013 |U R O LO G Y J O U R N A L Renal Access by Sonographer in PCNL | Wang et al REFERENCES 1. Fernstroem I, Johansson B. Percutaneous pyelolithoto- my. 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We encour- age urologists establish access by themselves during PCNL. CONFLICT OF INTEREST None declared.